Memory Alert: Even Slightly High Blood Pressure May Age Your Brain - And Even If You're Under 40

The white and gray matter of the brain are important in memory and thought (image from University of Maryland)

Researchers at the University of California at Davis released a study today that should give anyone with even mildly elevated blood pressure pause. It seems that having blood pressure higher than the optimal 120/80 may be aging your brain, putting you at risk for memory problems and eventually for dementia and Alzheimer's. And this appears to be true even for people in their thirties and even for people with pre-hypertension.

(This might include cutting back on salt today, says the American Heart Association (AHA) in a new advisory describing recent studies linking salt and heart disease risk.)

Using data from the highly regarded Framingham Heart Study, the UC Davis team led by professor of neurology Charles DeCarli compared detailed brain scans of 575 people who joined the study in 2009, most in their thirties. DeCarli and his team divided the participants into three groups: hypertensive, pre-hypertensive, and normal blood pressure. They then analyzed the gray and white matter of their brains using high-tech MRIs.

Previous studies have linked high blood pressure with memory loss, Alzheimer's, and dementia but this study, published online today in the November online version of The Lancet Neurology, appears to be the first one showing that the decline may begin as early as the 30s and 40s. Experts believe that stiffening or hardening of the arteries caused by high blood pressure gradually limits blood flow to the brain, depriving the brain of oxygen over time.

The scans used were both MRIs and diffusion tensor imaging, which obtains a micro view of the brain's white matter and the axons within it that carry electrical signals between different parts of the brain. According to the researchers, the brains of 30-year-olds with high blood pressure looked similar to the brains of people in their 40s who had normal blood pressure.

DeCarli wants the public to get the message that high blood pressure should be controlled to prevent brain aging, and this is true no matter what age you are. What this would mean is that people in their thirties should regularly get their blood pressure tested, something that most people don't do until they're older.

If your blood pressure is elevated, make lifestyle changes (lose weight, exercise, lower your salt intake) or take medication or both to lower it to below 120/80.

Back to Salt: Yes, you should cut out salt if you're pre-hypertensive or hypertensive. But actually, this applies to you no matter how healthy your numbers, the AHA announced this week. In fact, cutting out salt might be one of the fastest and easiest fixes all of us can make to save our brains.

According to the AHA, eating more than the recommended 1500 milligrams a day puts you at direct risk of high blood pressure. (This is in direct contradiction of a couple of much-touted studies saying salt isn't so bad.) Yet in America we consume an average of 3400 milligrams a day; more than twice what we should. While people with hypertension and heart disease are always advised by doctors to eat less salt, the AHA wants all of us to do this, whether or not our blood pressure is currently in the normal range. "The entire U.S. population, not just at risk groups" should restrict salt to 1500 milligrams, says Nancy Brown, chief executive officer of the AHA.